Some Properties of Human Skeletal Muscle Creatine Kinase

Abstract

Creatine kinase has been purified from human skeletal muscle. The properties of the human enzyme are similar to those of the enzyme from rabbit muscle. The molecular weight was determined as approximately SO 000 with a probable two reactive sulphydryl groups per molecule. Manganous (II) ion was almost as effective as magnesium as the activating metal ion, and calcium and cobalt could also act in this capacity. Under standardized conditions the nucleotide specificity was ADP > dADP > IDP > GDP > UDP > XDP in the reverse reaction. No hydrolytic activity was observed with ATP.Initial velocity and product inhibition studies were used to determine various kinetic constants for the substrates of the enzyme. It was concluded that, as for the rabbit muscle enzyme, the reaction probably followed a rapid equilibrium random mechanism. Anomalous kinetic behaviour, however, was observed for the forward reaction for MgATp 2 -but not for creatine, when measurements were extended over a much wider range than normally used. The reciprocal plot of velocity as a function of substrate concentration gave a curve, concave downwards, instead of a straight line.

Macro-Creatine Kinase-BB: Observations on 6 Patients

“…The atypical migration of the enzyme activity is obviously due to its high molecular weight (M T = 250,000) compared to the molecular weight of native creatine kinase isoenzymes (M T = 80,000, (15,16) (8), this is also the case for 5 of the six reported patients. The alteredM/c/zae//s constants of the creatine kinase-BB enzyme thus could be explained by steric hindrance.…”

Creatine kinase activity inhibitor in sera from patients with muscle disease

“…In humans, its molecular weight is approximately 80,000 (10) and it exists as a dimer in several isoenzymic forms. Its role in regenerating ATP from phosphorylcreatine is widely recognized.…”

Eastern Grey Kangaroo Muscle Creatine Kinase

“…The procedure has proved reproducible (five preparations) with a range of specific activities from IImol min-1 mg-1 . The specific activity may be compared with values of 125 and 108 units for the enzyme from rabbit muscle and human muscle, respectively (Keutel et al 1972; Lee et al 1977). The purified enzyme contained only one protein band by polyacrylamide gel electrophoresis (Fig.…”